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Many people have relocated their filter with very little loss of pressure. That shouldn't be an issue. I'm still thinking that, based on your symptoms, that you have a cavitation problem. Unfortunately, the only wa to check is to pull the pan. You didn't say what kind of Canton pan you have but I have the road race pan on mine. The pickup has got to be for that pan. Most other pickups stick down too far below the pump housing. It's an easy mistake to make.
Here is a pic of my Canton pan and the correct pickup on the pump. They've got to be ordered as a set. See if you have a receipt for both.
Notice how the pickup is almost flush with the bottom of the pan. Stock pumps and pickups aren't like that.
Thanks, I will check out my receipts and see what I bought. it was a while back but I have everything somewhere.
Again, this is one of those replies that starts with, "your gonna have to drop your pan"; sorry about that. I don't think your oil is making it back into the pan at high rpms. And I don't necessarily believe that it's being held back (up) in the heads / lifter valley. Could be that your builder installed or reinstalled a factory baffle below the crank. Factory technology (at least with small blocks) is to use a flat plate; they call it a windage tray...which like its name implies is designed to keep the "windage" generated by the rotating crankshaft from blowing oil away from the oil pump pickup. Unfortunately, it also acts as a restriction to oil return; the oil flying off the crankshaft assembly hits that flat surface and tends to bounce back up into the crank; net result, less oil to the pump, especially at higher rpm.
Modern windage trays either have built in louvers or expanded mesh designed to "strip" this flying oil away from the crankshaft and direct it down into the pan and to the pump pickup.
The picture of the Canton pan shows such a baffle built into the pan itself.
In my own experience, I have used a Milodon "Diamond Stripper" baffle that mounts off of the main bearings studs and can be adjusted very close to the crankshaft (1/8th inch) and must be very efficient because my use of a big block (high volume / high pressure) pump in a small block with a stock 5 quart oil pan reveals no pressure loss at high rpm.
Conventional wisdom would suggest that the big block oil pump will suck the pan dry before the oil could return to the sump, but apparently, with the right combination of windage tray/baffles, and pump pickup placement, that doesn't happen.
So, as much as of an inconvenience as it would be, I suggest dropping the pan and taking a look at what's really down there. And god only knows, you wouldn't be the first one to find a shop rag where it would be least expected
Many people have relocated their filter with very little loss of pressure. That shouldn't be an issue.
Originally Posted by 1963SS
I'm still thinking that, based on your symptoms, that you have a cavitation problem.
I'm leery on this one. Why? B/c...cavitation would be caused by a resistance to flow on the inlet side -a clogged pick up or one too close to the pan -as 1963SS is suggesting. When would this problem be the WORST? When the oil is cold, thick and more adverse to flow and at high RPM (not load dependent.)
But that is the opposite of what we see happening. You problem occurs when the oil thins, and is more able to flow.
To ME, the problem seems more like you're emptying the pan (drain back not fast enough). I didn't see a "2-5k RPM "LONG pulls"...were the cold 2-5k as long in duration as the hot one? If you just run around for a bit, at say, 4k RPM, little to no load, will pressure drop and take a while to recover? Have I understood the conditions correctly?
Originally Posted by Gareth
I gather that for some reason under sustained throttle input the oil is not getting back to the pump.
Your problem occurs when the oil thins, and is more able to flow.
To ME, the problem seems more like you're emptying the pan (drain back not fast enough). I didn't see a "2-5k RPM "LONG pulls"...were the cold 2-5k as long in duration as the hot one? If you just run around for a bit, at say, 4k RPM, little to no load, will pressure drop and take a while to recover? Have I understood the conditions correctly?
I tried to be as scientific as possible but my methodology breaks down a little on durations - watching where I am going, watching that if the pressure drops I'm off the gas asap and feeling what grip the back end has during the pulls gets a little busy in my head!
You are correct, I cannot say that the duration of the cold tests was the same as the warm ones. The 'no load' ones are a direct comparison. I can probably do some constant 4K runs if I stay in second gear to see if the pressure drops.
I have all I need now to fit a manual gauge at the weekend to compare the results - weather permitting.
I can probably do some constant 4K runs if I stay in second gear to see if the pressure drops.
I have all I need now to fit a manual gauge at the weekend to compare the results - weather permitting.
Thanks
I would do that. No need to accelerate, just determine if the pump sucks oil, and the oil is returning over a time period, with high volume. That should help separate if the problem is volume related, or TQ related.
I would do that. No need to accelerate, just determine if the pump sucks oil, and the oil is returning over a time period, with high volume. That should help separate if the problem is volume related, or TQ related.
Ok, further testing shows that at constant loads up to 4000 rpm the oil pressure is stable. The issues happens when you climb through the gears accelerating hard.
Ok, further testing shows that at constant loads up to 4000 rpm the oil pressure is stable. The issues happens when you climb through the gears accelerating hard.
This weekend the mechanical gauge goes on.....
I think it's safe to say that it's not a pick up restriction, or a drain back issue, then. At 4000 RPM, you're pumping a lot of oil, and you didn't lose pressure.
I guess, the next thing I'd do is put the engine under max load (tq) somehow, and observe the pressure. Like climbing a steep hill, WOT, high gear...or something like that.
I'll be interested to see what the mechanical gauge reads.
I think it's safe to say that it's not a pick up restriction, or a drain back issue, then. At 4000 RPM, you're pumping a lot of oil, and you didn't lose pressure.
I guess, the next thing I'd do is put the engine under max load (tq) somehow, and observe the pressure. Like climbing a steep hill, WOT, high gear...or something like that.
I'll be interested to see what the mechanical gauge reads.
Gauge plumbing done, just need to mount the gauge externally somehow. Ran out of time because I had to change the indicator bulb in my daily driver - which meant removing the front end of the car... but that's Renaults for you!
Well after a lot of mucking about it appears that my oil pressure problems were most likely oil pump bind and fixed with some spacers under the distributor.
I have a miniram I casting but it was heavily modified for 1206 ports. I had 5mm spacer plates welded onto the manifold which meant the whole intake sat higher. I milled down the Dizzy boss to suit but it seems to have unsettled the oil pump geometry which i suspect got worse the hotter the engine and the oil got. Since changing the spacing I have not had any further occurances of low oil pressure.
Thanks to all those who posted
Originally Posted by Gareth
*****UPDATED WITH RESULTS 05/10/2015***********
Hi,
Finally got my car running with my 427 and had a few fun test drives. The car drives fine, no shortage of power and torque!
I have noticed however that the car runs hotter than before - the dash shows 190 - 230 despite having a huge Becool rad in it. Oil temp is about 180 and there is plenty of new synthetic oil in it.
The bug worry is the oil pressure. When the car is cold it hovers around the 50psi mark. As the car gets warned up tick over drops to about 34 but under load it drops, sometimes enough for the warning light to come on.
However, I am a bit worried about the accuracy of the digital cluster. The FAST system shows the Temperature to be much lower (160 to 180). The battery volts are always about 2 -3 volts off what I read at the battery.
Anything recommended or what could cause the oil pressure to be low?
Well after a lot of mucking about it appears that my oil pressure problems were most likely oil pump bind and fixed with some spacers under the distributor.
I have a miniram I casting but it was heavily modified for 1206 ports. I had 5mm spacer plates welded onto the manifold which meant the whole intake sat higher. I milled down the Dizzy boss to suit but it seems to have unsettled the oil pump geometry which i suspect got worse the hotter the engine and the oil got. Since changing the spacing I have not had any further occurances of low oil pressure.
Thanks to all those who posted
So this problem was caused by your modified distributor?
Well after a lot of mucking about it appears that my oil pressure problems were most likely oil pump bind and fixed with some spacers under the distributor.
I have a miniram I casting but it was heavily modified for 1206 ports. I had 5mm spacer plates welded onto the manifold which meant the whole intake sat higher. I milled down the Dizzy boss to suit but it seems to have unsettled the oil pump geometry which i suspect got worse the hotter the engine and the oil got. Since changing the spacing I have not had any further occurances of low oil pressure.
Thanks to all those who posted
NOT TO BE A NAY SAYER, BUT anytime you change all those factory dimensions, you have to double check EVERYTHING.
Pull the distributor, put a shim kit...readily available for a few bucks ...on the distributor shaft between the distributor housing and distributor gear; this limits the shaft vertical play to 0.015 inch or so. once that dimension is set, the distributor shaft and gear isn't going to rise or change as the cam gear tries to move the distributor gear upward, and you can see with some certainty where the distributor gear is engaging the cam gear.
With all your changes, it could be spot on, it could be high, it could be low. coat the distributor gear with machinist blue, permanent marker, heavy grease, whatever. Reinstall the distributor and turn the engine over a few times, enough to show you where the actual engagement is occurring on the distributor gear.
I stress this because improper engagement can lead to a stripped distributor gear...or as my wife said, "the engine made a terrible sound and there was no oil pressure". And if the gear on the cam gets damaged in the process...bad becomes worse.
This can be checked even better with the pan off, which allows checking the play between the oil pump drive shaft and the pump...too little...possible binding issues as you have previously noted, but way too much ain't good either. Plus you can verify the pump pickup to pan bottom clearance.
Good luck. I am sure you have a sizeable amount of money in your build...and I wouldn't take any chances with the oil system.
Two things of note, PLEASE change those fittings on your oil hose; gradually oil will work its way into the fitting, the hoses will soften with heat...and BLOOOEY...the hose will blow off.
Second check that you have the right oil filter; I am fairly certain that your aftermarket filter mount does not have a built in oil pressure bypass valve to route oil around an clogged, or becoming clogged oil filter; stock chevy filters do not have an internal bypass valve...the bypass valve is in the oil filter mounting boss. Ford style filters I believe do. ANYWAY, if the mount doesn't have a bypass valve, and the filter doesn't have one, your engine may be starving for oil as it tries to push all the oil through a too small or partially clogged oil filter...and this can happen; its happened to me.
NOT TO BE A NAY SAYER, BUT anytime you change all those factory dimensions, you have to double check EVERYTHING.
Pull the distributor, put a shim kit...readily available for a few bucks ...on the distributor shaft between the distributor housing and distributor gear; this limits the shaft vertical play to 0.015 inch or so. once that dimension is set, the distributor shaft and gear isn't going to rise or change as the cam gear tries to move the distributor gear upward, and you can see with some certainty where the distributor gear is engaging the cam gear.
With all your changes, it could be spot on, it could be high, it could be low. coat the distributor gear with machinist blue, permanent marker, heavy grease, whatever. Reinstall the distributor and turn the engine over a few times, enough to show you where the actual engagement is occurring on the distributor gear.
I stress this because improper engagement can lead to a stripped distributor gear...or as my wife said, "the engine made a terrible sound and there was no oil pressure". And if the gear on the cam gets damaged in the process...bad becomes worse.
This can be checked even better with the pan off, which allows checking the play between the oil pump drive shaft and the pump...too little...possible binding issues as you have previously noted, but way too much ain't good either. Plus you can verify the pump pickup to pan bottom clearance.
Good luck. I am sure you have a sizeable amount of money in your build...and I wouldn't take any chances with the oil system.
Two things of note, PLEASE change those fittings on your oil hose; gradually oil will work its way into the fitting, the hoses will soften with heat...and BLOOOEY...the hose will blow off.
Second check that you have the right oil filter; I am fairly certain that your aftermarket filter mount does not have a built in oil pressure bypass valve to route oil around an clogged, or becoming clogged oil filter; stock chevy filters do not have an internal bypass valve...the bypass valve is in the oil filter mounting boss. Ford style filters I believe do. ANYWAY, if the mount doesn't have a bypass valve, and the filter doesn't have one, your engine may be starving for oil as it tries to push all the oil through a too small or partially clogged oil filter...and this can happen; its happened to me.
Makes a lot of sense, thanks I will try the clearance checking methods without the removing the pan and see how confident I feel. I didnt shim the distributor a huge amount, probably only 0.1" with the gaskets.
The oil relocation kit was from Mr Gasket if I remember correctly and had a very basic bi-pass valve in the casting - and a Ford racing filter. I will have to dig out the specs to see how the filter I have now is configured but it is brand new.
Makes a lot of sense, thanks I will try the clearance checking methods without the removing the pan and see how confident I feel. I didnt shim the distributor a huge amount, probably only 0.1" with the gaskets.
The oil relocation kit was from Mr Gasket if I remember correctly and had a very basic bi-pass valve in the casting - and a Ford racing filter. I will have to dig out the specs to see how the filter I have now is configured but it is brand new.
WHat fittings would you suggest?
check out a aerquip catalog; or go to a local race shop or aircraft maintenance facility; that stuff's pretty universal
10-06-2015, 05:04 PM
